Alcohol use disorder (AUD) is often accompanied by psychiatric affective disorders, including anxiety and depression. With the rising prevalence in the USA and worldwide, AUD/affective disorder has become a serious public health issue. Unfortunately, effective prevention and treatment strategies for this disorder are hampered by our lack of understanding of the mechanisms underlying its development and progression. The goal of this proposal is to identify a previously unrecognized mechanism by which stress-driven deficiency of BC1 RNA induces cortical synaptic dysfunction, which underlies the comorbidity of AUD/affective disorders. Recently, we discovered, for the first time, a causal link between epigenetic dysregulation of synaptic molecules in the medial prefrontal cortex (mPFC) and AUD/affective disorder phenotypes in the offspring of prenatally restraint stressed dams (here defined as PRS mouse). We found that young adult PRS mice exhibited heightened anxiety- like behaviors which were associated with increased ethanol consumption compared to non-stressed (NS) offspring. Further studies revealed that the behavioral deficits in PRS mice were characterized by a decrease in cortical dendritic spine density and key synaptic molecules that govern spine formation and function, including PSD95 (post synaptic density 95) and ARC (activity regulated cytoskeleton associated protein). BC1 RNA (brain cytoplasmic1 RNA, here defined as BC1), a long non-coding RNA highly expressed in mammalian cortex, plays a pivotal role in neuronal translational control and is essential for synaptic plasticity. Our pilot studies show that BC1 expression was significantly decreased in synaptoneurosomes prepared from mPFC of PRS mice compared to NS counterparts. Strikingly, RNA pull-down with BC1 probe revealed highly enriched mRNAs encoding key synaptic proteins, including PSD95 and ARC, suggesting that these mRNAs could be modulated by BC1 in tuning synaptic functions. In addition, prenatal stress elicited overexpression of histone deacetylases (HDACs) which resulted in the reduction of BC1. Taken together, BC1 may be a key factor in the development of AUD/affective disorder comorbidity. We hypothesize that epigenetic repression of BC1 induced by prenatal stress will disrupt local translation of mRNAs at dendritic synapses, which will alter synaptic development and function, contributing to the comorbidity of AUD/affective disorders. The targeted normalization of cortical BC1 will restore synaptic function and rescue AUD-like behaviors in PRS mice. The hypothesis will be tested in our unique mouse model of AUD/affective disorders using a series of cutting-edge molecular approaches. This project will set a foundation for intricate studies aimed at defining the novel role(s) of non-coding RNA(s) in regulating synaptic function to advance our understanding of the complex interplay between stress and the development of comorbidity of AUD/affective disorders. This could have far-reaching implications in the targeted design and development of new pharmacological agents towards the treatment of these disorders at epigenetic levels.